Implement PDF function, closes #20 (#114)

pkg/html/dynamic/document.go

@@ -698,6 +698,17 @@ func (doc *HTMLDocument) NavigateForward(skip values.Int, timeout values.Int) (v
 	return values.True, nil
 }
 
+func (doc *HTMLDocument) PrintToPDF(params *page.PrintToPDFArgs) (core.Value, error) {
+	ctx := context.Background()
+	
+	reply, err := doc.client.Page.PrintToPDF(ctx, params)
+	if err != nil {
+		return values.None, err
+	}
+
+	return values.NewBinary(reply.Data), nil
+}
+
 func (doc *HTMLDocument) CaptureScreenshot(params *ScreenshotArgs) (core.Value, error) {
 	ctx := context.Background()
 	metrics, err := doc.client.Page.GetLayoutMetrics(ctx)

pkg/stdlib/html/blob.go

@@ -3,6 +3,9 @@ package html
 import (
 	"context"
 	"fmt"
+	"regexp"
+
+	"github.com/mafredri/cdp/protocol/page"
 
 	"github.com/MontFerret/ferret/pkg/html/dynamic"
 	"github.com/MontFerret/ferret/pkg/runtime/values"
@@ -10,6 +13,31 @@ import (
 	"github.com/MontFerret/ferret/pkg/runtime/core"
 )
 
+func ValidateDocument(ctx context.Context, value core.Value) (core.Value, error) {
+	err := core.ValidateType(value, core.HTMLDocumentType, core.StringType)
+	if err != nil {
+		return values.None, err
+	}
+
+	var doc *dynamic.HTMLDocument
+	var ok bool
+	if value.Type() == core.StringType {
+		buf, err := Document(ctx, value, values.NewBoolean(true))
+		if err != nil {
+			return values.None, err
+		}
+		doc, ok = buf.(*dynamic.HTMLDocument)
+	} else {
+		doc, ok = value.(*dynamic.HTMLDocument)
+	}
+
+	if !ok {
+		return nil, core.Error(core.ErrInvalidType, "expected dynamic document")
+	}
+
+	return doc, nil
+}
+
 /*
  * Take a screenshot of the current page.
  * @param source (Document) - Document.
@@ -35,22 +63,12 @@ func Screenshot(ctx context.Context, args ...core.Value) (core.Value, error) {
 		return values.None, err
 	}
 
-	var doc *dynamic.HTMLDocument
+	val, err := ValidateDocument(ctx, arg1)
-	var ok bool
-	if arg1.Type() == core.StringType {
-		buf, err := Document(ctx, arg1, values.NewBoolean(true))
 	if err != nil {
 		return values.None, err
 	}
-		doc, ok = buf.(*dynamic.HTMLDocument)
+	doc := val.(*dynamic.HTMLDocument)
 	defer doc.Close()
-	} else {
-		doc, ok = arg1.(*dynamic.HTMLDocument)
-	}
-
-	if !ok {
-		return values.None, core.Error(core.ErrInvalidType, "expected dynamic document")
-	}
 
 	screenshotParams := &dynamic.ScreenshotArgs{
 		X:       0,
@@ -145,3 +163,217 @@ func Screenshot(ctx context.Context, args ...core.Value) (core.Value, error) {
 
 	return scr, nil
 }
+
+func ValidatePageRanges(pageRanges string) (bool, error) {
+	match, err := regexp.Match(`^(([1-9][0-9]*|[1-9][0-9]*)(\s*-\s*|\s*,\s*|))*$`, []byte(pageRanges))
+	if err != nil {
+		return false, err
+	}
+	return match, nil
+}
+
+/*
+ * Print a PDF of the current page.
+ * @param source (Document) - Document.
+ * @param params (Object) - Optional, An object containing the following properties :
+ *   Landscape (Bool) - Paper orientation. Defaults to false.
+ *   DisplayHeaderFooter (Bool) - Display header and footer. Defaults to false.
+ *   PrintBackground (Bool) - Print background graphics. Defaults to false.
+ *   Scale (Float64) - Scale of the webpage rendering. Defaults to 1.
+ *   PaperWidth (Float64) - Paper width in inches. Defaults to 8.5 inches.
+ *   PaperHeight (Float64) - Paper height in inches. Defaults to 11 inches.
+ *   MarginTop (Float64) - Top margin in inches. Defaults to 1cm (~0.4 inches).
+ *   MarginBottom (Float64) - Bottom margin in inches. Defaults to 1cm (~0.4 inches).
+ *   MarginLeft (Float64) - Left margin in inches. Defaults to 1cm (~0.4 inches).
+ *   MarginRight (Float64) - Right margin in inches. Defaults to 1cm (~0.4 inches).
+ *   PageRanges (String) - Paper ranges to print, e.g., '1-5, 8, 11-13'. Defaults to the empty string, which means print all pages.
+ *   IgnoreInvalidPageRanges (Bool) - to silently ignore invalid but successfully parsed page ranges, such as '3-2'. Defaults to false.
+ *   HeaderTemplate (String) - HTML template for the print header. Should be valid HTML markup with following classes used to inject printing values into them: - `date`: formatted print date - `title`: document title - `url`: document location - `pageNumber`: current page number - `totalPages`: total pages in the document For example, `<span class=title></span>` would generate span containing the title.
+ *   FooterTemplate (String) - HTML template for the print footer. Should use the same format as the `headerTemplate`.
+ *   PreferCSSPageSize (Bool) - Whether or not to prefer page size as defined by css. Defaults to false, in which case the content will be scaled to fit the paper size. *
+ * @returns data (Binary) - Returns a base64 encoded string in binary format.
+ */
+func PDF(ctx context.Context, args ...core.Value) (core.Value, error) {
+	err := core.ValidateArgs(args, 1, 2)
+	if err != nil {
+		return values.None, err
+	}
+
+	arg1 := args[0]
+	val, err := ValidateDocument(ctx, arg1)
+	if err != nil {
+		return values.None, err
+	}
+	doc := val.(*dynamic.HTMLDocument)
+	defer doc.Close()
+
+	pdfParams := page.NewPrintToPDFArgs()
+
+	if len(args) == 2 {
+		arg2 := args[1]
+		err = core.ValidateType(arg2, core.ObjectType)
+		if err != nil {
+			return values.None, err
+		}
+		params, ok := arg2.(*values.Object)
+		if !ok {
+			return values.None, core.Error(core.ErrInvalidType, "expected object")
+		}
+
+		landscape, found := params.Get("landscape")
+		if found {
+			err = core.ValidateType(landscape, core.BooleanType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetLandscape(landscape.Unwrap().(bool))
+		}
+		displayHeaderFooter, found := params.Get("displayHeaderFooter")
+		if found {
+			err = core.ValidateType(displayHeaderFooter, core.BooleanType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetDisplayHeaderFooter(displayHeaderFooter.Unwrap().(bool))
+		}
+		printBackground, found := params.Get("printBackground")
+		if found {
+			err = core.ValidateType(printBackground, core.BooleanType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetPrintBackground(printBackground.Unwrap().(bool))
+		}
+		scale, found := params.Get("scale")
+		if found {
+			err = core.ValidateType(scale, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if scale.Type() == core.IntType {
+				scale = values.Float(scale.(values.Int))
+			}
+			pdfParams.SetScale(scale.Unwrap().(float64))
+		}
+		paperWidth, found := params.Get("paperWidth")
+		if found {
+			err = core.ValidateType(paperWidth, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if paperWidth.Type() == core.IntType {
+				paperWidth = values.Float(paperWidth.(values.Int))
+			}
+			pdfParams.SetPaperWidth(paperWidth.Unwrap().(float64))
+		}
+		paperHeight, found := params.Get("paperHeight")
+		if found {
+			err = core.ValidateType(paperHeight, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if paperHeight.Type() == core.IntType {
+				paperHeight = values.Float(paperHeight.(values.Int))
+			}
+			pdfParams.SetPaperHeight(paperHeight.Unwrap().(float64))
+		}
+		marginTop, found := params.Get("marginTop")
+		if found {
+			err = core.ValidateType(marginTop, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if marginTop.Type() == core.IntType {
+				marginTop = values.Float(marginTop.(values.Int))
+			}
+			pdfParams.SetMarginTop(marginTop.Unwrap().(float64))
+		}
+		marginBottom, found := params.Get("marginBottom")
+		if found {
+			err = core.ValidateType(marginBottom, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if marginBottom.Type() == core.IntType {
+				marginBottom = values.Float(marginBottom.(values.Int))
+			}
+			pdfParams.SetMarginBottom(marginBottom.Unwrap().(float64))
+		}
+		marginLeft, found := params.Get("marginLeft")
+		if found {
+			err = core.ValidateType(marginLeft, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if marginLeft.Type() == core.IntType {
+				marginLeft = values.Float(marginLeft.(values.Int))
+			}
+			pdfParams.SetMarginLeft(marginLeft.Unwrap().(float64))
+		}
+		marginRight, found := params.Get("marginRight")
+		if found {
+			err = core.ValidateType(marginRight, core.FloatType, core.IntType)
+			if err != nil {
+				return values.None, err
+			}
+			if marginRight.Type() == core.IntType {
+				marginRight = values.Float(marginRight.(values.Int))
+			}
+			pdfParams.SetMarginRight(marginRight.Unwrap().(float64))
+		}
+		pageRanges, found := params.Get("pageRanges")
+		if found {
+			err = core.ValidateType(pageRanges, core.StringType)
+			if err != nil {
+				return values.None, err
+			}
+			validate, err := ValidatePageRanges(pageRanges.String())
+			if err != nil {
+				return values.None, err
+			}
+			if !validate {
+				return values.None, core.Error(core.ErrInvalidArgument, fmt.Sprintf(`page ranges "%s", not valid`, pageRanges.String()))
+			}
+			pdfParams.SetPageRanges(pageRanges.String())
+		}
+		ignoreInvalidPageRanges, found := params.Get("ignoreInvalidPageRanges")
+		if found {
+			err = core.ValidateType(ignoreInvalidPageRanges, core.BooleanType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetIgnoreInvalidPageRanges(ignoreInvalidPageRanges.Unwrap().(bool))
+		}
+		headerTemplate, found := params.Get("headerTemplate")
+		if found {
+			err = core.ValidateType(headerTemplate, core.StringType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetHeaderTemplate(headerTemplate.String())
+		}
+		footerTemplate, found := params.Get("footerTemplate")
+		if found {
+			err = core.ValidateType(footerTemplate, core.StringType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetFooterTemplate(footerTemplate.String())
+		}
+		preferCSSPageSize, found := params.Get("preferCSSPageSize")
+		if found {
+			err = core.ValidateType(preferCSSPageSize, core.BooleanType)
+			if err != nil {
+				return values.None, err
+			}
+			pdfParams.SetPreferCSSPageSize(preferCSSPageSize.Unwrap().(bool))
+		}
+	}
+
+	pdf, err := doc.PrintToPDF(pdfParams)
+	if err != nil {
+		return values.None, err
+	}
+
+	return pdf, nil
+}

pkg/stdlib/html/lib.go

@@ -33,5 +33,6 @@ func NewLib() map[string]core.Function {
 		"INNER_TEXT":       InnerText,
 		"INNER_TEXT_ALL":   InnerTextAll,
 		"SCREENSHOT":       Screenshot,
+		"PDF":							PDF,
 	}
 }